Other than the obvious need for sunshine, what do solar cars and their teams have to contend with to make it down the Stuart Highway from Darwin to Adelaide?

Weather

Ideally, the sun would shine the entire 3,000km of the race, but when it doesn't, teams must be prepared to quickly change their strategy and the designs of their cars.

Cars in the Cruiser category — vehicles designed for practicality instead of just speed — are allowed to recharge by generator, but get higher efficiency scores if they can avoid that and run on solar they've stored during the day.

The speed-focused Challenger-category cars, however, are not allowed to charge at all, meaning the clouds play a bigger role — ultimately determining whether the cars stay in the race or not.

This year's event proved particularly tricky, with overcast weather plaguing teams as they approached Central Australia, forcing a number of teams to pack their cars onto trailers before the cut-off time of 5:00pm.

On overcast days, the solar arrays on Queensland's TeamArrow car gathered about 15 per cent of the power they would normally get on a bright sunny day, chief technical officer Cameron Tuesley said.

Harsh environment

Mr Tuesley said having a team that was flexible and responded to issues collaboratively was crucial for success on the challenge.

"You really have to work as a cohesive unit. Problems are ... the nature of the beast with this thing," he said.

He said there were often big issues, and with an experimental vehicle traveling across a very harsh environment "things go wrong all the time".

"It's how they respond. What you've really got to be able to do is not just respond quickly and dynamically but also in a multi-disciplinary way.

"It's one of the great joys of working on a project like this."

Even though the cars need the sun to function, it is a doubled-edged sword.

Inside the cars can get extremely hot, usually a few degrees above the ambient temperature outside, given air-conditioning and efficiency do not go hand in hand.

It compounds the pressure on drivers to navigate road conditions, process the efficiency information coming from the solar arrays, and communicate with their convoys.

The heat is tough on the cars, too. Day one of the race saw temperatures near 40 degrees Celsius, putting Queensland's TeamArrow's battery at serious threat of overheating.

To make matters worse, the mandatory check points — called control stops — are usually on bitumen and radiate heat back up to the car, which is especially an issue for teams arriving in the middle of the day.